Other Assets, Accrued Expenses and Other Liabilities (Tables) - USD ($) $ in Millions	Jun. 30, 2020	Oct. 01, 2019	Sep. 30, 2019
Segment Reporting Information [Line Items]
Receivables, net	$ 0.8		$ 1.1
Notes Receivable, Related Parties	6.5		0.0
Operating Lease, Right-of-Use Asset	3.2	$ 2.7	0.0
Prepaid expenses	5.3		3.4
Land purchase contract deposits	5.8		5.1
Other assets	5.5		4.1
Total Other assets	27.1		13.7
Accrued employee compensation and benefits	3.8		5.6
Accrued property taxes	2.9		2.1
Operating Lease, Liability	3.4	$ 2.9	0.0
Accrued interest	11.0		13.5
Contract liabilities	0.3		2.5
Deferred income	9.4		9.3
Accrued Development Costs	32.4		35.4
Other accrued expenses	5.1		8.4
Other liabilities	4.7		2.8
Total Accrued expenses and other liabilities	$ 73.0		$ 79.6